The subject invention is directed a method of contactively engaging a hologram recording film with a master hologram via static charge attraction.
Copies of holograms are commonly made by positioning hologram recording film adjacent to a master hologram, and then exposing the hologram recording film by illuminating the master hologram with reconstruction illumination. In this process, it is important that the recording film and the master hologram be fixedly positioned parallel to each other so that there is virtually no relative movement between the recording film and the master hologram during the holographic exposure. In practice, this relative motion must be no greater than a fraction of the wavelength of the exposure laser light, typically less than 500 Angstroms. In addition, it is necessary that a close to constant optical refractive index be provided between the recording film and the master hologram.
Known techniques for fixedly positioning a hologram recording film relative to a master hologram include weighting or the use of a vacuum chuck. In laboratory reproduction, a hand roller might be used to fixedly position hologram recording film relative to a master hologram. An important consideration with known techniques in general is the required expenditure of time, which prevents high rate copying. Weighting and the use of a vacuum chuck require different arrangements and/or equipment for transmission holograms and for reflection holograms.